Technical Abstract:
Identification of genes involved in seed and root colonization by biocontrol bacteria may allow for strategies for improved ecological fitness, survival, and performance by these strains. <i>Enterobacter cloacae<i/> strain M59, containing a single transposon insertion, was reduced in colonization of cucumber seeds relative to wild-type strain 501R3 but unaffected in control of <i>Pythium ultimum<i/> damping-off on cucumber. DNA sequence analysis indicated that the transposon was inserted in <i>cyaA<i/>, which encodes adenylate cyclase. The growth profile of strain M59 was consistent with a <i>cyaA<i/> mutant. Adenylate cyclase catalyzes the production of cAMP, which in conjunction with CRP, positively regulates several catabolic and other unrelated functions.